Ocean Diurnal Variations Measured by the
Korean Geostationary Ocean Color Imager
Menghua Wang1, Lide Jiang1,2, Seunghyun Son1,2, & Wei Shi1,2
1 NOAA/NESDIS
Center for Satellite Applications & Research (STAR)
College Park, MD, USA
2 CIRA, Colorado State University, Fort Collins, CO, USA
July 24th, 2013
at ‘CoRP 9th Annual Science Symposium’ in Madison, Wisconsin
COMS-1 – Communication, Ocean and
Meteorological Satellite
GOCI Introduction
412nm Yellow substance and turbidity
443nm Chlorophyll absorption maximum
490nm Chlorophyll and other pigments
555nm Turbidity, suspended sediment
660nm
Baseline of fluorescence signal,
Chlorophyll, suspended sediment
680nm
Atmospheric correction and fluorescence
signal
745nm
Atmospheric correction and baseline of
fluorescence signal
865nm
Aerosol optical thickness, vegetation,
water vapor reference over the ocean
NOAA-MSL12 Processing for GOCI data
 Collaboration effort between NOAA/NESDIS/STAR and KIOST/KOSC.
 NOAA-MSL12 data processing (based on NASA SeaDAS) is improved for
the GOCI data processing.
 Various parameters and lookup tables are generated, and a new
atmospheric correction algorithm has been developed for GOCI data
processing in the region (Wang et al., 2012; 2013).
 New cloud masking method has been recently developed for very turbid
coastal waters (e.g., Yangtz River mouth, Korean Coastal areas).
 The GOCI atmospheric correction algorithm is recently improved using
new vicarious calibration.
 GOCI Level-1B data (Mar. 2011﹣Feb. 2013) were obtained from the
Korea Ocean Satellite Center and processed using the new atmospheric
correction algorithm.
 In situ optical measurements (Mar.﹣Nov. 2011) are used to quantify and
validate GOCI ocean color products with the new atmospheric correction
algorithm for GOCI ocean color data processing.
Estimating NIR Contribution
•
•
•
nLw(748) = f(Kd(490)), f(x) = 0.465x-0.385x2+0.152x3-0.0121x4
nLw(869) = g(nLw(748)), g(x) = 0.368x+0.04x2
M. Wang, W. Shi, and L. Jiang, “Atmospheric correction using near-infrared bands
for satellite ocean color data processing in the turbid western Pacific region”,
Optical Express, 20(2), 741-753 (2012)
GOCI Coverage over Korean Peninsular
and location of in-situ measurements
*. In-situ bio-optical measurements are provided by KIOST/KOSC
GOCI Matchup Comparison
M. Wang, J.H. Ahn, L. Jiang, W. Shi, S. Son, Y.J. Park, and J.H. Ryu, “Ocean color
products from the Korean Geostationary Ocean Color Imager (GOCI)”, Optical
Express, 21(3), 3835-3849 (2013)
Matchup between in-situ and GOCI NOAA-MSL12 using New Gain
Mean Ratio of GOCI NOAA-MSL12 vs. In Situ
Var
Old (Wang et al. 2013)
New Gain
Avg (std)
No
Avg (std)
No
nLw(413)
1.2737 (0.599)
18
1.2433 (0.481)
17
nLw(443)
1.4182 (0.486)
18
1.0677 (0.300)
18
nLw(490)
1.2868 (0.357)
18
1.1125 (0.247)
18
nLw(555)
1.1506 (0.308)
18
1.1068 (0.242)
18
nLw(660)
1.3367 (0.531)
18
1.0990 (0.333)
16
nLw(680)
1.4092 (0.586)
17
1.1273 (0.339)
17
Spectral shape of in situ
and GOCI-derived nLw(λ)
measurements
Black-in situ, red-GOCI
ECS (Sep)
SW (Sep)
SW (Sep)
SW (Sep)
SW (Sep)
SW (Sep)
SW (Sep)
SW (Sep)
GOCI Composite Images
(2011 Mar. – 2012 Oct.)
Climatology GOCI Images from Mar. 2011 to Oct. 2012 (at 12:00)
Chl-a
Kd(490)
nLw(412)
nLw(443)
nLw(490)
nLw(555)
nLw(660)
nLw(680)
Monthly Composite Images of GOCI Kd(490)
(Mar. 2011 – Oct. 2012, at 12:00)
Time Series of GOCI Chl-a & Kd(490) Monthly Mean
(Mar. 2011 – Oct. 2012, at 12:00)
Chl-a
A
C
B
Kd(490)
A
C
B
GOCI Images for
Diurnal Changes
GOCI-MSL12 Chl-a (Apr. 5, 2011)
09h
10h
11h
12h
13h
14h
15h
16h
GOCI Images in
the East China Sea
GOCI NOAA-MSL12 Chl-a (2012-04-26)
Box1
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
Diurnal Changes
GOCI NOAA-MSL12 Kd(490) (2012-04-27)
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
GOCI NOAA-MSL12 Chl-a (2012-04-26)
GOCI NOAA-MSL12 Kd(490) (2012-04-26)
GOCI Images in
Hangzhou Bay & Lake Taihu
GOCI NOAA-MSL12 Kd(490) (2012-07-29)
GOCI Images in
the Bohai Sea
GOCI NOAA-MSL12 Kd(490) (2012-03-25)
09:00
10:00
11:00
12:00
14:00
15:00
16:00
Box1
13:00
Diurnal Changes
(Box1)
GOCI NOAA-MSL12 Kd(490) (2012-03-25)
GOCI NOAA-MSL12 Kd(490) (2012-08-23)
GOCI Images in
Dump Site in the Yellow Sea
GOCI NOAA-MSL12 Kd(490) (Jul. 19, 2011 )
09h
10h
11h
12h
13h
14h
15h
16h
Summary and Conclusions
 The GOCI ocean color products for the GOCI coverage region have been
derived using an iterative NIR-corrected atmospheric correction algorithm.
 Validation results show a reasonably good agreement between GOCI retrievals
and in situ measurements.
 This study demonstrates that GOCI ocean color products can be confidently
used to characterize and quantify the ocean environments as well as the
diurnal variability of the marine ecosystem in the western Pacific.
 This unique capability from geostationary satellite sensor can complement the
ocean color observations of other polar-orbiting satellites such as MODIS and
VIIRS, which have a global coverage but lack the temporal resolution to
monitor the dynamics of marine environments on an hourly basis.
Thank you!
GOCI NOAA-MSL12 Kd(490) (2012-08-23)
Backup
Spectral shape of in situ
and GOCI-derived nLw(λ)
measurements
Black-in situ, red-GOCI
JES (Mar.)
South (Apr.)
South (Apr.)
South (Apr.)
JES (May)
JES (May)
JES (May)
ECS (Aug)
GOCI-MSL12 Chl-a (Apr. 26, 2012)
09h
10h
11h
12h
13h
14h
15h
16h
GOCI-MSL12 Chl-a (Oct. 2, 2012)
09h
10h
11h
12h
13h
14h
15h
16h
GOCI-MSL12 Chl-a (Oct. 18, 2012)
09h
10h
11h
12h
13h
14h
15h
16h
GOCI NOAA-MSL12 Chl-a (Jul. 19, 2011 )
09h
10h
11h
12h
13h
14h
15h
16h
GOCI NOAA-MSL12 Kd(490) (2012-03-25)
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
GOCI NOAA-MSL12 Kd(490) (2012-03-25)
09:00
10:00
11:00
12:00
14:00
15:00
16:00
Box2
13:00
Diurnal Changes
(Box2)
GOCI NOAA-MSL12 Kd(490) (2012-08-23)
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
GOCI NOAA-MSL12 Chl-a (2012-07-29)
GOCI NOAA-MSL12 Chl-a (2012-04-27)
Box1
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
Diurnal Changes
GOCI NOAA-MSL12 Chl-a (2012-04-26)
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
GOCI NOAA-MSL12 Kd(490) (2012-04-26)
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
GOCI NOAA-MSL12 Chl-a (2012-04-27)
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00